Apparatus for producing slub yarn



Aug. 18, 1964 .wQE. STAMPS ETAL 3,144,745 I APPARATUS FOR PRODUCING SLUBYARN 3 Sheets-Sheet 1 Original Filed Aug. 26, 1958 Aug. 18, 1964 w. E.STAMPS ETAL 3,144,746

APPARATUS FOR PRODUCING SLUB YARN Original Filed Aug. 26, 1958 3Sheets-Sheet 2 Aug. 18, 1964 w. E. STAMPS ETAL v APPARATUS FOR PRODUCINGSLUB YARN Original .File d Aug. 26. 1958 5 Sheets- Shea: 3

United States Patent 3,144,746 APPARATUS FOR PRQDUCING SLUB YARN WilliamE. Stamps, Allen R. Merrill, and Malcolm Pt. Livingston, all ofCharlotte, N.C., assignors to Celanese Corporation of America, New York,N.Y., a corporation of Delaware Original application Aug. 26, 1958, Ser.No. 757,374, new Patent No. 3,044,251, dated July 17, 1962. Divided andthis application Mar. 27, 1962, er. No. 189,945

1 Claim. (Cl. 57-12) The present invention relates to novelty spun yarnsin which a spun yarn formed of staple fiber is formed with stablecockled slubs spaced apart along the length of the yarn.

Heretofore yarns containing cockled slubs have been producedunintentionally in spinning mills when attempting to spin fiber blendscontaining too much over-length staple. Such slubs are caused by a localinclusion of more than the normal number of fibers in a typicalcrosssection, and are generally unstable, being supported by only a fewlong fibers, and cause great difficulties in later processing. When suchslubs are encountered in normal processing, the stock is nearly alwaystaken out of work and scrapped and the staple supplier is called upon toreplace the defective staple.

In accordance with the present invention there is provided a yarn withcockled slubs which are highly resistant to removal and are reinforcedby segments of a preformed yarn embedded therein. The slubs of theinvention are further characterized in some instances by being shorterand thicker than those produced by known mechanical slubbing methods orfrom so-called self-slub fiber blends. The invention includes theslub-containing spun yarn which is produced as well as methods andapparatus for the production thereof.

In accordance with one aspect of the invention, a pre formed yarn ispassed together with at least one roving between the forward rolls of adrafting device. The preformed yarn may comprise a continuous filamentyarn made up of one or more continuous filaments which may or may not betwisted or it may comprise a spun yarn composed of staple fibers, butfor ease of reference this embodiment will be further described using acontinuous filament as the pre-formed yarn. The roving is supplied at arate less than the feed velocity of the forward rolls so that the rovingis drafted. The continuous filament is similarly supplied at a rate lessthan the feed velocity of the forward rolls so that it is under tensionin the drafting zone. The drafted roving and the continuous filamentissue together from the forward roll and are twisted by the spinningring surrounding the take-up bobbin.

The tension on the continuous filament in the drafting device isdetermined by the linear speed at which it is fed, the linear speed atwhich the forward roll of the drafting device operates and the weightingof the forward roll. Under a given set of linear speeds this weightingshould be insufficient to break the continuous filament in the draftingdevice to avoid forming a free end which might not be carried beneaththe forward roll.

Without wishing to be bound thereby, it is believed that the tensionwhich holds back the continuous filament causes the drafted roving inadvance of the forward roll to pile up about the slowly suppliedcontinuous filament to form a slub. At the same time, the twist appliedby the ring spinner to the continuous filament in advance of the forwardroll causes it to become tightly twisted until it breaks. Upon breakageof the continuous filament, the slub is completed and the roving orrovings supplied by the forward rolls are twisted in conventional mannerto form a length of conventional spun yarn until the leading end of thecontinuous filament which is slowly advanced by the forward rolls isagain caught in the twist of the spun yarn which is produced whereuponthe slub-forming process is repeated until the continuous filament isagain broken to complete formation of another slub having a short lengthof continuous filament yarn embedded therein.

As will be evident, the rate of twist and the rate of continuousfilament supply must be adjusted so that the continuous filament istwisted fast enough to continuously increase the number of twists perunit of length whereby the twist will increase to the breaking point. Aswill be evident, the twist build-up will be more rapid and breakage willoccur sooner with slower filament supply and also with more rapidtwisting. Similarly, breakage will occur more rapidly in filamentshaving a lesser capacity for resisting twist.

When the forward rolls are sufficiently weighted to draft the roving,they will normally bear sulficiently upon the continuous filament toprevent the twist from passing through the forward rolls into thedrafting zone. The filament is thus twisted more and more tightlyagainst the point where the filament is engaged and prevented fromrotating by the forward rolls. I

As employed herein the term roving has reference to a loose strand ofstaple fibers having either a low twist or no twist in which case it issometimes called a sliver.

The length and thickness of the slub which is produced will vary, itbeing evident that the slub will be longer when more length of filamentpasses through the forward rolls before breakage occurs. Thus, longerslubs can be formed by increasing the rate of filament supply, or byselecting a filament which requires a greater twist before it will breakor by pre-twisting the filament in the opposite direction from the twistbeing applied in the spinning process. The thickness of the slub isbasically determined by the difference between the rate of feed of theroving and the rate of feed of the continuous filament by the forwardrolls. If both are supplied to the forward rolls at the rate of the backrolls of the drafting device, then the difference in front roll feedvelocity will be substa'ntially indicated by the drafting ratio. Thus,at a drafting ratio of 15:1, the roving will emerge from forward rollsat a rate about 15 times faster than the filament. The greater thedifference in feed velocities (or the greater the drafting ratio), thegreater will be the thickness of the slubs which are produced. Draftingratios of from 5:1 to 40:1 are usable in accordance with the invention,drafting ratios of from 10:1 to 25:1 being preferred. At draft ratiosless than 5:1, long irregular slubs are formed which makes processing ofthe yarn difficult. At draft ratios above 40:1 the slubs are very smalland unstable.

In this manner, it is feasible to produce by the invention slubs whichare thicker and shorter (and therefore more visible) than can beproduced in other manner.

When the invention is performed using a plurality of rovings, as ispreferred, those portions of the product between the slubs will besimilar to conventional spun yarns produced by drafting and twistingseveral rovings with no continuous filament feed.

When one or more rovings are passed through a drafting device togetherwith a yarn which passes only through the front rolls, this yarn is notdrawn and the roving or rovings which are drawn are twisted about theyarn which is not drawn to produce a core yarn in which the yarn whichis not drawn forms a core about which the drawn roving or rovings areWrapped.

In the invention, a core yarn is not produced because the continuousfilament which corresponds to the core of the art does not extendthroughout the spun yarn but is only present in spaced apart segments,and because where the continuous filament is present, it has 33 issuedforth from the front rolls at a very much slower rate than the rovingsso that an increased thickness is obtained by multiple wrappings ofroving or rovings and some of the wrappings are opposite in directionwith respect to the direction of wrappings in the segments of spun yarnbetween adjacent slubs.

The invention will be more fully understood from the description whichfollows taken in conjunction with the accompanying drawings in which:

FIG. 1 is a side elevation diagrammatically illustrating the procedureof the invention together with the equipment employed for carrying outthe process on a schematic basis;

FIGS. 2-7, inclusive, are partial perspective views illustrating in astep-by-step manner and on an enlarged scale the formation of cockledslubs in accordance with the present invention.

In a preferred form of the present invention a plurality of rovings aresupplied and one of these rovings carries the continuous filament withit for the purpose of maintaining the supply of continuous filament inassociation with the rovings until these reach the forward rolls.

Referring more particularly to FIG. 1, a cored roving containing acontinuous filament core 11 is led to a drafting zone, preferably fromthe upper deck of a spinning frame creel (not shown). The cored roving10 is shown passing a guide bar 12 into a trumpet guide 13 where it isjoined in the form of the inveniton illustrated by a regular roving 14.The regular roving 14 passes beneath control roll 15 which bears againsta driving roll 16 about which the conventional drafting apron 17 istrained, the apron 17 being tensioned and guided by roll 18 and slidingagainst the member 19 to complete its triangular path adjacent the frontor forward rolls. The regular roving then passes beneath the backdrafting rolls 20 and 21 and is stretched in passing through thedrafting zone to the front drafting rolls or forward rolls 22 and 23.Rolls 21 and 23 are weighted by weight W which bears upon axles 36 and37. Weight W is brought to bear by means of saddle which rests uponaxles 36 and 37 and is connected to weight W by means of a mechanicallinkage. The mechanical linkage between saddle 35 and weight W comprisesarm 37 and lever 38. Arm 37 is attached at one end portion to saddle 35by means of pivot pin 36 and at the other end portion to lever 38. Lever38 at one end portion is hooked into the eye of eyebolt 39 and at theother end portion supports weight W which is pendent therefrom. Eyebolt39 is attached to front beam of the drafting frame.

The cored roving 10 travels a somewhat different path going above theroll 24 and then beneath the control roll 15 in order to applyadditional tension to the continuous filament 11. As will be evident,the particular manner in which the continuous filament is tensioned toregulate its supply velocity is not an important feature of theinvention. Thus, the weighting of the back rolls 20 and 21 can beincreased or the cored roving may be supplied from a roll driven atpredetermined speed or the cored roving supplied through feed rollsdriven at predetermined speed so that the continuous filament 11 issupplied under tension at a controlled rate less than the peripheralvelocity of the forward rolls 22 and 23.

The composite of rovings 10 and 14 and continuous filament 11 whichpasses through the forward rolls 22 and 23 is generically identified bythe numeral 25 and it contains spaced longitudinal segments 26, whichare conventional spun yarn in structure, alternated with spaced apartcockled slubs 27, the structure of which as well as the manner offormation of which will be more fully described hereinafter. Thecomposite yarn 25 is continuously twisted, as indicated by the arrow,and taken up in conventional manner by a vertically reciprocating ringspinner and rotating bobbin mechanism indicated generally at 28.

Referring more particularly to FIG. 2, this figure pictures a cockledslub produced in accordance with the invention and also shows the slubproducing mechanism immediately prior to slub production. Moreparticularly, there is shown in FIG. 2, the forward rolls 22 and 23 withthe rovings 10 and 14 being fed forwardly therefrom together with theforward end of a segment of the continuous filament 11. An end portionof saddle 35 bears upon axle 37. As will be seen, the rovings 1t) and 14are twisted together by the spinning indicated by arrow 28 to produce aspun yarn segment 26 of the composite slub yarn 25. There has beenpreviously produced a cockled slub 27. As will be seen, the slub 27comprises a more-or-less centrally positioned continuous filamentsegment 29 which extends through the slub 27. The trailing end of thecontinuous filament segment 29 is shown twisted in to the forward end ofthe spun yarn segment 26 as is indicated by the numeral 30. It will beobserved that some of the wrappings indicated by the numeral 31 aretwisted in an opposite direction with respect to the direction of twistin the spun yarn segment 26. The manner in which the oppositely twistedwrappings 31 are produced will be more fully described hereinafter.

Whereas FIG. 2 illustrates the slub forming mechanism immediately priorto the start thereof, FIG. 3, pictures the start of the slub formingmechanism. As will be seen in FIG. 3, the leading end of the continuousfilament 11 has been caught in the twist of the spun yarn segment 26and, as twisting as indicated by arrow 28 continues, the continuousfilament 11 becomes twisted forwardly of its point of engagement withthe forward rolls 22 and 23. This twisting is indicated by the numeral32.

As previously explained, and as will be seen by reference to FIGS. 3, 4,and 5, the rovings 10 and 14 are fed forwardly by the forward rolls 22and 23 more rapidly than the continuous filament 11. As a result, thewrappings 31 are produced, FIG. 4 showing the start of the production ofwrappings 31 and FIG. 5 showing a further stage in the production of thewrappings 31. It will be seen that the wrappings 31 start at thetrailing end of the spun yarn which is produced and move forwardly ofthe yarn (a direction opposite to the direction in which the spun yarnsegment 26 is produced). As spinning indicated by arrow 28 continues,the twist in filament 11 becomes tighter as is indicated at 32' and 32".

FIG. 6 pictures the cockled slub an instant after breakage of thecontinuous filament 11 as a result of excessive twist. At the instant ofbreakage, the cockled slub 27 is relieved of the restraining influenceof the continuous filament and moves forwardly as indicated by arrow 33and the excess of rovings 10 and 14 wrap around the inner reversewrappings 31 to form outer wrappings 34. The trailing end of thecontinuous filament segment 29 is still free of the rovings 10 and 14 atthe stage of slub production indicated in FIG. 6.

The completed cockled slub is illustrated in FIG. 7 where it will beseen that the trailing end of the continuous filament segment 29 hasbeen wrapped into the forward end of the new spun yarn segment 26 andthe leading end of the continuous filament 11 just protrudes frombetween the nip of the forward rolls 22 and 23. As will be evident, therovings 10 and 14 are spun together by the spinning indicated at 28 toproduce a further spun yarn segment 26, the result of this furtherspinning restoring the conditions shown in FIG. 2. Finally, the spunyarn segment 26 will catch the forward end of the continuous filament 11as pictured in FIG. 3 and the slub producing process will be repeated.

As will be evident, the cockled slubs of the invention possessextraordinary resistance to removal. In the invention, the cockle isconstituted by wrapped rovings which are integral with the rovingsconstituting the body of the spun yarn and these slubs are reinforcedwith a The invention is illustrated in the accompanying table segment ofcontinuous filament. In many instances, the in which a regular roving iscombined with a cored roving spun yarn of the invention will breakbefore the cockled to produce slub-containing yarns in accordance withthe slubs which are formed therein can be pulled out. invention.

Table Twist 1 Front Yarn Count 1 Core Roving With Regular Draft RollsSlub Gore Roving Ratio Werght- Character Nominal Actual ing, oz. NominalActual 100 denier cellulose acetate- 2.0 hank cellu- 2.0 hank cellu-15:1 17 t.p.i. Z. 20 t.p.i. Z. 12 15/1 /1 3X yarn diam. low twist. loseacetate. lose acetate. and 14 long. 100 denier rayonlow twist. 2.0 hankcellu- 2.0 hank eellu- 20:1 19 t.p.1. Z..- 24 t.p.1. Z... 10 20/1 13/14X yarn diam. lose triacetate. lose triacetate. I and long. 100 denierrayon40 t.p.i. do do 15:1 13 t.p.1. Z..- 21 t.p.1. Z... 16 15/1 7/1 4Xyarn diam. S twist. 1and 1-1V,)'

ong. 75 denier cellulose acetate 2.5 hank rayon.. 2.5 hank cellu- 15:115 t.p.i. Z... 18 t.p.i. Z... 10 19/1 12/1 Small and low twist. loseacetate. short.

1 NOTE.TWiStS and counts are average values over considerable lengths.While slub size and slub spacing may be controlled to 20 It is to beunderstood that the foregoing detailed desome extent as has beenindicated hereinbefore, the proscription is given merely by way ofillustration and that cedure of the invention causes slub formation andslub many variations may be made therein without departing size to berandom to a considerable extent. This appears from the spirit of ourinvention.

to be because the exact instant and point of filament This applicationis a division of our application Serial breakage will vary from one slubto the next and the pre- No. 757,374, filed August 26, 1958, now US.Patent No. cise instant of engagement between the spun yarn segment3,044,251, granted July 17, 1962.

and the leading end of the slowly advancing continuous Having describedour invention what we desire to sefilament is not preciselypredetermined. Since the concure by Letters Patent is: tinuous filamentis under tension with the forward rolls Apparatus for producing aslub-containing spun yarn slipping and skidding with respect thereto,the forward comprising a pair of drafting rolls and means to rotatemovement of the continuous filament is not completely e same, means tosupply at least one roving to said uniform and this appears tocontribute to the random drafting T0118 at a Velocity less than thePeriphera1 Velocformation of slubs which is experienced in accordance yof said aftihg r0115 50 that Said roving Will be drafted With theinvention. thereby, means to supply a pre-formed yarn to said draft-Specimens f h S1ub t i i s yam of h i ing rolls together with saidroving with said pre-formed vfi t n have en quilled and Woven as fillingin a runyarn being supplied under tension at a velocity less than ningwarp and also as the Warp, and still further with the the Peripheralvelocity of said t g rolls, means t slub-containing yarn of theinvention constituting both Weight Said drafting T0113 suihcifihfly todraft Said roving fill and warp. Very few of the slubs were pulled outand and insufliciently break Said PIE-formed Y before most of the slubswithstood fabrication to produce deco- 40 TeaChihg Said drafting T011550 that Said life-formed Y rated woven f bri will be fed through saiddrafting rolls at a slower velocity When woven into a fabric, the slubsprovide a textured than Said g, and means to twist the composite ofappearance which is uni-directional when the novel yarn Said Preformed Yand Said roving emerging from Said is employed t constitute eithe thwarpor th weft forward rolls at a rate suflicient to cause the twist insaid It will be understood that the yarns of the invention may P Y tobuild P until Said Pmformed Y be employed, if desired, to constituteboth warp and weft. breaks- In this event, a roughened appearance isobtained in the final woven product. The appearance characteristics andReferences Cited m the file of thls patent the hand of the fabrics whichmay be woven can be con- UNITED STATES N S siderably varied by variationin the thickness, length, and 2,210,884 Chittenden et al. Aug. 13, 1940spacing of the slubs in the yarn which is employed as will 2,880,566Schlums Apr. 7, 1959 be evident to those skilled in the art. 2,990,673Adkins July 4, 1 961

